Discovery of well preserved Cretaceous carnivorous dinosaur footprints in Gulin, Sichuan Province

On July 6, 2021, the dinosaur footprint research team of China University of Geosciences (Beijing) announced that a group of well preserved dinosaur footprints have been discovered in Huangjing Town, Gulin County, Luzhou City, Sichuan Province. The most important discovery is a new species of eubrontes, named eubrontes nobitai. The paper was published in the Journal of paleogeography on May 5.

The picture shows the footprints of carnivorous dinosaurs in Gulin, Sichuan Province. Picture provided by research team (same below)

In July 2020, when Lin Yongping, a villager of Yuanlin village, Huangjing Town, Gulin, was cleaning up the river channel blocked by collapsed rocks after the rainstorm, he found that there were four footprints with uniform spacing on a stone slab washed over by the flood. These footprints were of uniform size, and each footprints had three fat toes arranged closely. The spacing between each footprints was about 50 cm. Xu Ting, a government official of Huangjing Town, who had found many dinosaur footprints in Hanxi village, Guihua Town, Gulin County, came to take photos of the footprints and sent them to relevant experts. Later, paleontologists from China University of Geosciences (Beijing) and Zigong Dinosaur Museum led the team to Jinyuxi. Through careful investigation, it was found that at least four sauropods, two theropods and four isolated tracks were distributed in the footprints of Jinyuxi. There are water ripple marks on the surface of sandstones where footprints are preserved, and mud cracks are generally developed in siltstones, which represent the interbedding of meandering river deposits and small braided river deposits. In addition, there are abundant invertebrate traces in the feldspar quartz sandstone, such as arenicolites and taenidium.

The most important discovery of Jinyuxi footprint is a new species of eubrontes, named eubrontes nobitai. According to the obvious footprints of the metatarsophalangeal pad of the second toe, they were classified as the footprints of stylosaurus. In addition, these specimens are also obviously different from the footprints of medium to large scale theropods with the thumb footprints, such as Chongqing footprints, other footprints of stylosaurus, kayentapus footprints and Cretaceous Asian footprints, Therefore, a new species was named.

Photo: a close-up of the tracks of carnivorous dinosaurs in Gulin, Sichuan.

It is estimated that the speed of the maker is 3.89 km / h and the body length is about 4 meters. There are almost no theropod dinosaur bones in the lower Cretaceous of Sichuan Basin, but according to the early Cretaceous fossil records in Western China, it can be inferred that the middle-sized allosauridae or carcharodontosauridae dinosaurs may have formed the trace.

The earliest footprints of shirairon were found in the Connecticut Valley of Massachusetts in the early 19th century. The reports of shilelung footprints or eubrontes type footprints are common in the upper Triassic, Jurassic and Cretaceous strata. At present, more than 100 footprints in China have produced three toed theropod footprints, and a large part of them are classified as stylosaurus footprints or stylosaurus footprints. Although there are abundant footprints of stylosaurus, its footprints have been updated many times. Most of the footprints are poorly described, so at present most scholars only accept one, which is e. giganteus. In addition to E. giganteus, the footprints of E. nobilis may be one of the most specific species.

The footprints of stylosaurus yebyi are an important type of theropod footprints. It is the only one of the theropod footprints in China that is similar to the Jurassic stylosaurus footprints. It can be said that the footprints of leiosaurus nobilis are the first reliable Cretaceous record species of leiosaurus. They are also rare new relic species named after careful study. Its appearance in the lower Cretaceous of Southwest China proves the existence of a successful evolutionary theropod dinosaur branch, coexisting with the makers of megalosauripus, changpeipus, therangospodus and other types of footprints, It may be helpful for us to better understand the spatial and temporal changes of stylosaurus and stylosaurus footprints in the future.

This research was completed in cooperation with Professor Martin g. lockley of University of Colorado Denver, Hendrik Klein, a German footprint scholar, Peng Guangzhao and ye Yong of Zigong Dinosaur Museum.